An anecdote from 1990s continental Europe. A friend of mine, upon reaching a status of a "high-net worth individual", was invited to invest in a hedge fund ass

An anecdote from 1990s continental Europe. A friend of mine, upon reaching a status of a "high-net worth individual", was invited to invest in a hedge fund associated with a bank of regional importance (major for that small country). They demonstrated the best of the tech of the time, and then shifted the tone to, "but we also use more traditional approaches". Unusually large portion of their "consulting research staff" was female and spread Europe-wide. Not because they were progressive or pursuing diversity agenda; these were call girls. The call girls were paid for timely tips. Even if they only report that a particular top executive stayed overnight far away from home, was in a foul mood, and a couple of top-ranking colleagues were present, this can be used to detect an significant internal event not reported publicly. If the girl was crafty enough to extract more information, even better.